The user is allowed to register a reserved IOVA range by using the
DMA MAP API and setting the new flag: VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA.
It provides the base address and the size. This region is stored in the
vfio_dma rb tree. At that point the iova range is not mapped to any target
address yet. The host kernel will use those iova when needed, typically
when the VFIO-PCI device allocates its MSI's.
This patch also handles the destruction of the reserved binding RB-tree and
domain's iova_domains.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>
---
- Currently the user is not yet informed about the number of pages to
provide
RFC v1 -> RFC v2:
- takes into account Alex comments, based on
[RFC PATCH 1/6] vfio: Add interface for add/del reserved iova region:
- use the existing dma map/unmap ioctl interface with a flag to register
a reserved IOVA range. A single reserved iova region is allowed.
---
drivers/vfio/vfio_iommu_type1.c | 98 ++++++++++++++++++++++++++++++++++++++++-
include/uapi/linux/vfio.h | 9 ++++
2 files changed, 106 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 2f085d3..37c7d78 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -538,10 +538,40 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
vfio_lock_acct(-unlocked);
}
+/* vfio_unmap_reserved: unmap and free all reserved binding nodes
+ * for all domains and destroy their iova_domain
+ *
+ * @iommu: iommu handle
+ */
+static void vfio_unmap_reserved(struct vfio_iommu *iommu)
+{
+ struct vfio_domain *d;
+
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ struct rb_node *node;
+
+ while ((node = rb_first(&d->reserved_binding_list))) {
+ struct vfio_reserved_binding *b =
+ rb_entry(node,
+ struct vfio_reserved_binding, node);
+
+ while (!kref_put(&b->kref,
+ vfio_reserved_binding_release)) {
+ }
+ }
+ d->reserved_binding_list = RB_ROOT;
+
+ put_iova_domain(d->reserved_iova_domain);
+ kfree(d->reserved_iova_domain);
+ }
+}
+
static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
{
if (likely(dma->type != VFIO_IOVA_RESERVED))
vfio_unmap_unpin(iommu, dma);
+ else
+ vfio_unmap_reserved(iommu);
vfio_unlink_dma(iommu, dma);
kfree(dma);
}
@@ -785,6 +815,68 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
return ret;
}
+static int vfio_register_reserved_iova_range(struct vfio_iommu *iommu,
+ struct vfio_iommu_type1_dma_map *map)
+{
+ dma_addr_t iova = map->iova;
+ size_t size = map->size;
+ uint64_t mask;
+ struct vfio_dma *dma;
+ int ret = 0;
+ struct vfio_domain *d;
+ unsigned long order;
+
+ /* Verify that none of our __u64 fields overflow */
+ if (map->size != size || map->iova != iova)
+ return -EINVAL;
+
+ order = __ffs(vfio_pgsize_bitmap(iommu));
+ mask = ((uint64_t)1 << order) - 1;
+
+ WARN_ON(mask & PAGE_MASK);
+
+ /* we currently only support MSI_RESERVED_IOVA */
+ if (!(map->flags & VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA))
+ return -EINVAL;
+
+ if (!size || (size | iova) & mask)
+ return -EINVAL;
+
+ /* Don't allow IOVA address wrap */
+ if (iova + size - 1 < iova)
+ return -EINVAL;
+
+ mutex_lock(&iommu->lock);
+
+ /* check if the iova domain has not been instantiated already*/
+ d = list_first_entry(&iommu->domain_list,
+ struct vfio_domain, next);
+
+ if (d->reserved_iova_domain || vfio_find_dma(iommu, iova, size)) {
+ ret = -EEXIST;
+ goto out;
+ }
+
+ dma = kzalloc(sizeof(*dma), GFP_KERNEL);
+ if (!dma) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ dma->iova = iova;
+ dma->size = size;
+ dma->type = VFIO_IOVA_RESERVED;
+
+ vfio_link_dma(iommu, dma);
+
+ list_for_each_entry(d, &iommu->domain_list, next)
+ alloc_reserved_iova_domain(d, iova, size, order);
+
+out:
+ mutex_unlock(&iommu->lock);
+ return ret;
+}
+
static int vfio_bus_type(struct device *dev, void *data)
{
struct bus_type **bus = data;
@@ -1297,7 +1389,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
} else if (cmd == VFIO_IOMMU_MAP_DMA) {
struct vfio_iommu_type1_dma_map map;
uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
- VFIO_DMA_MAP_FLAG_WRITE;
+ VFIO_DMA_MAP_FLAG_WRITE |
+ VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA;
minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
@@ -1307,6 +1400,9 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
if (map.argsz < minsz || map.flags & ~mask)
return -EINVAL;
+ if (map.flags & VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA)
+ return vfio_register_reserved_iova_range(iommu, &map);
+
return vfio_dma_do_map(iommu, &map);
} else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 43e183b..982e326 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -411,12 +411,21 @@ struct vfio_iommu_type1_info {
*
* Map process virtual addresses to IO virtual addresses using the
* provided struct vfio_dma_map. Caller sets argsz. READ &/ WRITE required.
+ *
+ * In case MSI_RESERVED_IOVA is set, the API only aims at registering an IOVA
+ * region which will be used on some platforms to map the host MSI frame.
+ * in that specific case, vaddr and prot are ignored. The requirement for
+ * provisioning such IOVA range can be checked by calling VFIO_IOMMU_GET_INFO
+ * with the VFIO_IOMMU_INFO_REQUIRE_MSI_MAP attribute. A single
+ * MSI_RESERVED_IOVA region can be registered
*/
struct vfio_iommu_type1_dma_map {
__u32 argsz;
__u32 flags;
#define VFIO_DMA_MAP_FLAG_READ (1 << 0) /* readable from device */
#define VFIO_DMA_MAP_FLAG_WRITE (1 << 1) /* writable from device */
+/* reserved iova for MSI vectors*/
+#define VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA (1 << 2)
__u64 vaddr; /* Process virtual address */
__u64 iova; /* IO virtual address */
__u64 size; /* Size of mapping (bytes) */
--
1.9.1
--
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